


Complimentary

by echoflowertea



Series: Open Requests [14]
Category: Undertale (Video Game)
Genre: F/M, Female Reader, Reader Is Not Frisk
Language: English
Status: Completed
Published: 2016-08-20
Updated: 2016-08-20
Packaged: 2018-08-10 00:18:38
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,028
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7822921
Author URL: https://archiveofourown.org/users/echoflowertea/pseuds/echoflowertea
Summary: <blockquote class="userstuff">
              <p>You’ve got a way with music, and Sans wants to be part of that world.</p>
            </blockquote>





	Complimentary

**Author's Note:**

> **prompt** : I wanna start off by saying that I love everything you've written on your blog, it always makes me smile!!! I hope it's not too much trouble to request a gnarly fem reader trying to teach Sans to shred the gnar which only leads to his frustration?? Lots of love, Nonny! ;o

Being a scientist and engineer, Sans had quite the love affair with math.

He could appreciate the simple beauties of numbers. All it took was a little creativity and know-how and he could create something incredible. It had been longer than he would’ve liked to get back involved in his experiments. He swore it off after a lot of…questionable things that happened in the past. But with time and encouragement, he found himself more interested than ever.

He brushed up on his calculus. Solved complex expressions on his chalkboard at home. Crafted tiny little things to annoy his brother. Added attachments on everyday items to test his theories and ideas. And the more that he did it, the more comfortable he became with delving back into old habits. He could work at his own pace and not worry about questionable ethics. He could plan his own days and forget all about a time past where he forced himself to swallow the discomfort and think of a “greater good”.

Today was the unveiling of one of his newest projects. Something that he knew you would love. Being a musician of sorts, you had a really difficult time finding the most helpful and long-lasting equipment. He thought he’d solved a minor problem and wanted to hand it off to you. Maybe his was anticipating your reaction more than anyone else who had commissioned works for him. That was to be expected – he did have the softest of spots for you, after all.

He let himself into your apartment. You’d always left the door unlocked for him when you anticipated his arrival, which made his SOUL throb almost painfully.

“hey.”

You glanced up from the bed, dressed in nothing but a long t-shirt and your hair pinned up away from your face. Phew. He reached up to wipe the beads of sweat that threatened to teeter down his browbone, feeling a little weak in the knees at your relaxed appearance.

“Oh man, I’m glad you’re here. I have something I wanted to show you!”

He did, too, but he would let you go first. He liked to watch the cute expressions blossom across your face when you played.

You grabbed the sheet music you had and shoved it toward his chest. “I know you can’t read music, but this is my newest thing. It’s a…um…”

He scanned over it all, though it really was like a foreign language. He had no clue what it all meant, but the excitement in your eyes was enough to bring a genuine grin on his face. “what?”

“You know what? How ‘bout I just play it for you?”

He settled down on the edge of your bed, fixing his gaze on the way you handled your guitar. Something you had personalized for your own use. Your favorite color and with stickers that illustrated the kind of quirky and interesting woman he’d fallen for. And taped on the back was a picture of the two of you, a quick snapshot that his brother took the night you first said you loved him. It was his favorite decoration, if was going to be honest.

You positioned your fingers on the strings and strummed along. Plucking at them with deftness and an accuracy that made his chest tighten. Damn, you were always so good at this. He watched you with wonder and amazement, the notes floating in the air toward him and seemingly wrapping around his head.

The song itself was something insanely passionate. You poured your heart into the song, and whatever it was about, you were really going at it. Concentrating on the practiced motions as the beats and rhythms drowned out everything. If he had a heart, it would be beating along with the tune. You hummed along with the music and the world around him faded. Fingers plucking and creating something that resounded in his head when he looked straight at you.

You finished and gazed at him bashfully. He returned the look with his own heated stare.

“So? What did you think?”

“babe. you know it’s incredible.”

“Really?” You laughed. “Oh man, thanks! I was trying to put together something for our next open mic night. I figured I should go with something a little softer since it’ll be ladies night. If we’re going to be honest, it was inspired by…um…you.”

He couldn’t contain himself any more. “what, was it a love song?”

“All my songs are love songs, Sans. Some are just a little more broken up than others.” You set the guitar on the bed and leaned in close to him, just enough where he could see the stars in your eyes. “And that one in particular is, well, a ballad.”

“for me?”

“Yeah. For you. So, I’ll ask you again: what’d you think?”

He couldn’t take his eyes off you. In the entirety that he’d known you, he always thought that he’d reached a point where he couldn’t be surprised any more. You proved him wrong constantly.

“ok, i guess.”

“Yeah, right! You totally loved it. I can tell.”

You tackled him on the bed and he let you hover over him, peppering his face with kisses as his bones flushed. You always knew just what to say to get him flustered, too. He laughed and halfheartedly tried to stop your onslaught, instead finding his hand tangling in the mop of hair that you’d tried to shove back from your face. Lips meeting his mouth and practically devouring him whole, a pleasant buzz floating up from his spine to his chest.

You pulled back just enough to hover above him. Arms on either side of his shoulders. He could stay like this forever. Caged under you, the music still thrumming through his bones, a quirk of a smile on your lips and knowing that there was no going back to a time without you.

“i wanna play it.”

“Hmm?” You peeled away from him and tried to fix yourself back up, embarrassed that he’d already gotten you this flustered. He hadn’t even been here an hour, yet. “Play what?”

“your song.”

You froze. Sans? And your music? You hadn’t even considered it a possibility. The tune wasn’t too complex, you supposed you could show him the basic movements and get him to memorize the patterns rather than read the notes. Lots of people made that mistake when they were first learning how to play anything, so you could always let him give it a shot.

“Seriously?”

“yep. wanna…give it a shot. if that’s ok with you.”

“You know what?” You grabbed the guitar and settled down, cross-legged and beaming at him. “Let’s do this! C’mere. We’re going in on this thing.”

Sans crawled back over to where you sat. You angled the guitar toward him and made sure to get him to focus on your hands.

“I think we can get started on some small pieces of the song and work our way up. So let’s get going. Now watch me.”

He did. Drinking in the flow of your movements, how the strings swayed underneath your touch like they were made for each other. His pupils flitted back and forth while he did his best to remember each short burst.

“Think you wanna give it a try?”

He took the entire thing into his lap and nearly toppled over the edge from its added weight. It was pretty much the same size as him, so he had a little difficulty in balancing it. He stopped swaying and did his best to mimic the position you took when playing.

“Here, lemme help.” You reached over and bent his elbow a little further. Bringing it up so that it wasn’t keeping him down so much.

He sucked in a breath and went to work.

_Scr-scri scri scriiiii._

What the hell? That wasn’t…like what you did at all! Sans panicked and stopped what he was doing. He would start over. Maybe his fingers just weren’t at the right position after all. He narrowed his eyes and flicked the tips of them along. They just kept making that awful scratching noise, nothing even remotely close to music. In fact, it would’ve make any lesser monster’s ears bleed if they listened to it.

“Um, Sans…”

“hold on. think i got it.”

He put more effort into it. Pushing himself harder, now going into the flare and theatrics of it. He couldn’t mess this up. You’d shared this with him and put everything into this song, so he would be damned if he didn’t recreate it. It didn’t have to be exact, but anything was better than this screeching that came out of the instrument you worked so beautifully.

He swung his arm in a long sweep, letting the final note dissipate along with the remnants of his confidence. He stared at the guitar. At his hands. At you. Then back again.

What happened? Why couldn’t he do it?

“That was…a really good try, Sans. Maybe we can go for it again and take things slow?”

You huddled next to him with a gentle smile. He didn’t deserve this much kindness. With a performance like that, he should’ve bombed and had you tell him so. But you were being patient because you knew that if you said anything even slightly negative, he probably would’ve crumbled and never touched this thing again.

You spent the next hour trying to get his fingers to stroke the strings with just the right amount of pressure. It felt like no matter how hard he tried, he just couldn’t get it. You didn’t even have a spare pick for him to use, either, as the majority of yours were lost between traveling and your other band members. So he was forced to listen to that awful attempt over and over again, not getting any closer to the haunting melodies you crafted from your heart.

Sans couldn’t bring himself to give it another go. He handed off the guitar to you with a strained chuckle.

“kinda got distracted with all this stuff. meant to come over and bring you this.”

You took it from his hands. It was…an old pasta box?

“look inside.”

That made a lot more sense. You tore it open.

No. Way.

You pulled the headset out and gaped. It was _amazing._ A technological wonder that was sure to change your entire life. You spent so much time trying to find the perfect microphone, but all of the equipment was way out of your price range and the stands weren’t exactly user friendly when you wanted to dance across the stage and sing. But this? With just the perfect volume setting that fit against your voice? You knew before you even turned it on that it was going to create record-like quality, silk on people’s ears, bringing that steady thrum that was sure to turn the crowds over to your full works.

“Holy shit. Sans, this is…”

“glad you like it.” He was embarrassed. “maybe you could try it out at the open mic night, huh?”

“Yeah. I think I will.” You set it down carefully and turned your attention to him. The guitar and his gift went long forgotten as you pinned him underneath your full weight, sealing your mouths together with a warm kiss.

Sans wasn’t going to give up this easily.

He went home and pulled up a variety of websites for him to deconstruct the instrument for all it was worth. When he first learned how to “play” the trombone, all it took was a few half-hearted tries and changing the shape of his mouth. It really didn’t need that much effort. Three keys and he was good to go. But with double the sets to handle, technique needed in operating it from top to bottom, _and_ making sure he could mirror the style and showmanship of your technique, he needed a lot more than just five minutes of half-assed practice.

He printed off diagrams. Set them up all over his lab. Poured over the mechanics of how it worked. Sat and thought about how he could work around the string issue. Maybe it was because of the texture of his bones? He crafted a few quick replacements and tried a pick that he crafted to fit along the hard curves of his metacarpals.

It was all about the rhythm and speed, careful touch and practice. He read up on musical theory. Looked at all of the different technicalities in musical composition. Tried to come to terms understanding the math behind it. Because he wasn’t very good at a lot of things, but he was with this subject. And he would be damned if he failed in something that was well within his area of expertise. All he had to do was apply his knowledge and he was set!

Wait. Shit. He didn’t even have one to practice with.

Okay, new plan: get a guitar. Practice. And wow you with his sudden rush of dedication.

You hadn’t heard from Sans in well over a week. You understood that he was a busy dude. But you really hoped that he hadn’t forgotten about your little show tonight. It really wasn’t that big of a deal, but you were going to showcase your song for the crowd. It would be nice if he was around to gauge their reactions.

Being a performer, nerves still got the best of you sometimes. But you knew that once you got out on stage, you would feel it melt away and drink in the crowd’s energy. You had friends here to watch you. Sans would be around, more than likely, and that was one of your biggest sources of inspiration. He would chase away any lingering fears with that supportive grin.

Ah, there he was! You spotted him come through the doors just as your name was called and you walked out to the stage. Everybody had their set ready, so it was just up to you to get started. With the rainbow-colored lights switching on and off behind you, the steady stream of the fog machine wrapping around your ankles, and the cheers of the crowd in front, you started up the song and went to work.

Music was math, Sans said. He told you that he respected what you did because it incorporated something he loved. You didn’t really view it the same way; you played because of the way it made you feel. Sure, you had to retain a little bit of know-how when engaging in a performance like this, composing music and writing it where it flowed well.

But this right here? This didn’t feel like the result of carefully calculated equations and summations of numerals. It was just you and the crowd interacting with your guitar as the medium, the song a reflection of who you were and what you stood for. A lyrical representation of your emotions and the very real feelings you had toward the skeleton monster in the front row of the crowd.

Sans watched you lock eyes with him as the music engulfed him in its familiar and steady warmth. A tale that you weaved about him. How the compliments and idealization reached his senses and left him pleasantly numb. You loved him so much. You wanted this entire place to know about it. And you would gladly share your complete and utter adoration for him with the world itself.

The lights went around you in a multicolored halo, the floating dust particles in the bar sparkling as they floated along. You locked eyes with him and refused to look at anyone else, not entertaining some of the more rambunctious members of the crowd while they cheered you on.

You picked up the pace and the rhythm turned hard as you reached the climax of the song, absolutely _shredding_ it as you went. Your fingers went into a flurry, dragging along and tearing at the still air like it was nothing. Breaking down the fabric of the soft music from before, riffs cracking and lashing out so sharply that he felt like he’d been punched in the gut.

The rest of the band joined in after your solo and finished off the rest of the track. People were already clapped and stamping their feet for an encore. You broke into a grin and graciously thanked them for their interest, but that you wanted some of the others waiting backstage to get their turn.

Everyone wanted to celebrate with some cold drinks and terrible barfood, but you broke away from them once you had the chance. You met Sans near the entranceway and grabbed for his hand before he could even think about reaching for you. Burying your face in his shoulder, you bent down just enough that you could wrap him up in a tight embrace.

“you were so damn good up there, babe. phenomenal.”

“I’m so glad you liked it.” You cupped his face and kissed him along his t-zone, liking the way he stammered out a halfhearted ‘stop’ so he could get some more words out. “I thought for sure I was going to mess up and get lost, but then I remembered the part we were practicing the other day and bounced back.”

“seriously? couldn’t even tell. you’re a natural.”

“Let’s grab a quick drink and then go home. I want to shower and get rid of all this sweat.” You gestured to your t-shirt, which admittedly was a lot more soaked in the pits than you would’ve liked.

“heh, ok. i’ll ask ‘em for a sippy cup.”

“Pfft, you wish!”

Sans didn’t really understand the appeal of drinking too much, but he would join in if you did. Mostly because he liked to watch the color sweep along your cheeks the tipsier you got. You only had a couple of beers, something to quench your thirst from singing so much. He was happy to nurse just one, slapping down fives like it was nobody’s business so he could pay for yours to celebrate.

It was a short walk back to his place. He insisted that you come over so he could show you what he’d been working on. This was going to be one of the most iconic reveals of his life so far.

He could hardly contain his excitement. He shed his jacket off the moment he stepped through the door, pushing you toward the basement stairs.

“Sans, whoa! Slow down!”

You got to the bottom step and made your way along the lab equipment. Sans had a huge setup down here once he got back into the swing of things. It was his pride and joy. In the middle of the room was a large table with various bits of metal and plastic scattered about.

He waltzed over to the object lying underneath a white sheet. Grinning so hard you could barely stand it.

“wanna see?”

“Hell yes! Don’t keep me waiting any more.”

“you sure?”

“Sans!!!”

He tore it off and waited for your reaction with bated breath.

You crept over and stared at it on wonder. It was…a guitar. But it looked…different than what you were used to. It was carved from metal instead of wood. There was a lot going on in the inside, too. Lots of dials and nodes that you weren’t sure what their purpose was. You ran your finger along the edge of it, the cold surface sending an unpleasant shiver down your spine. The only heartwarming part of it, if any, was the photo of you and Sans on the body of it. The very same you had haphazardly taped on your own.

“What…is this?”

“made some modifications to the basic design. still uses reverberations from the strings to produce sound, but with a different kind of catalyst. couldn’t get my bones to work with the regular stuff, and it was too quick for my hands. so i created somethin’ that would feed off my electrical energy instead.”

“Uh…?”

“more specifically, my magic.” He was beaming. What. A. Nerd. “can send a charge to the tips of my fingers and this material’s a good conductor for it. don’t even have to really touch it if i don’t want to, but i still gotta hold it the way you do and make the motions of strummin’. this part here? s'what picks up feedback from my SOUL and translates it, while this…”

He went on and on. You watched the excitement spread from his face to his gestures as he picked it up to show you all of the different parts. How he tweaked it to work along with his body. How he wasn’t going to put enough physical energy into it, but would manipulate his magical abilities to give him the same results. Working around the system, yet still maintaining his own signature skillset so it didn’t lose any charm.

“Sans…”

“huh?” He glanced up after strapping it all along his shoulder, the small instrument the perfect size for his tiny stature. “you, uh…want me to explain it again?”

“No. I want you to play me something.” You hopped up on the stool near the workbench, leaning backwards on your palms. “Please?”

“uh. ok. guess i could…”

He positioned himself. Looked at you. Swallowed. In all his time working on the thing, he never had a chance to actually…test it. Oh, it would work. But maybe it just wouldn’t live up to the hype he created for it.

Sans’s magic sparked. Channeling into the guitar through the strings as he tentatively brushed his fingers along. So far so good. Just…nothing as ear-shatteringly bad as the attempts he made before. But the notes themselves were unsure and almost shy, petering out before he had a chance to create something more than just a few of them at once.

“don’t wanna…y’know. disappoint ya.” He felt stupid even saying it.

You grinned at him. “You know I’m going to love it regardless of how it sounds. But just relax. This is about you and me.”

The two of you. Now that was math he could get behind. It was like going through an old proof that he knew was going to check out before he even started it. How the both of you complimented each other. Combined to create an entirely new equation that could be applied to nearly every situation with success.

A universal theorem! That was it!

He played for you. You watched his expression shift from mildly surprised to downright giddy. He was so damn proud of himself for doing this, and you were, too. None of what you taught him was being brought to the table, but you didn’t care. Not in the slightest.

You were hooked on the rhythm and beats. Closing your eyes and picturing everything that he painted for you. A response to your own song, something that addressed your worries and sent them spiraling away into nothingness. A love letter from his SOUL, crafting honeyed words with a track that was enough to leave you breathless.

When he finished, stretching out with a final note, he lifted his head up to meet your gaze.

“That’s how you really feel about me?”

He laughed. “kinda pathetic, huh?” He could feel his face getting hot, but wasn’t able to stifle his reaction any more. Not when he put it all out there.

“No.” You hopped down and closed the distance between you. Reaching down to grip his hands in yours, rubbing your thumbs over his joints affectionately. “I couldn’t have said it better myself.”

“thanks, babe. kind of…got carried away.”

You shrugged. This was just one of his defense mechanisms. Tear himself down so he didn’t think that he’d actually accomplished anything worth noting. Well, you were going to prove him wrong.

“A little, but that’s how I know it’s real. I couldn’t have asked for a better boyfriend, you know. Think we can schedule a time to play together?”

Sans already knew the outcome. Probability of success? One hundred percent.

**Author's Note:**

>  **comment!** it encourages me to continue writing and i respond to every one!
> 
> send me a fic request [**in my tumblr inbox**](http://echoflowertea.tumblr.com/ask)!
> 
> want to [donate](http://ko-fi.com/A258IM#_=_)? i would really appreciate it!


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